The present invention relates generally to methods and apparatus for treating eating disorders using intragastric (“IG”) balloons, and more particularly to techniques for treating patients with overeating disorders, especially obese patients, by using an IG balloon having an integrated electrophysiologically active transducer system. An integrated electrophysiologically active transducer allows for the generation of a range of acoustic waveforms within the saline solution that fills the balloon and propagates to the sidewalls of the balloon. Such waveform propagation amplifies and modulates the stimulus to the satiety receptors lying within the wall of the stomach, sending afferent signals through the vagus nerve to the brain and thereby diminishing hunger, as well as furnishing the central nervous system with a general sense of wellness, contentment and satiety.
Obesity is a serious and widespread health problem facing the world today. Classic treatment options for obese people include nutritional counseling, dieting and exercise. Such treatments, however, have demonstrated relatively poor long-term success rates. Surgical procedures including gastric restriction in cases of severe obesity have shown some success, although such procedures necessitate major surgery and have high morbidity and mortality rates.
IG balloons are a known treatment alternative to the more commonly known options such as bariatric surgery, diet suppression medication, psychotherapy, physical exercise and surgery. Generally, the practice involves placing a deflated IG balloon into the stomach of a patient and then expanding the IG balloon by instillation of saline solution or a relatively inert gas such as nitrogen, thus effectively reducing the available area within the stomach and limiting capacity for food through its space occupying presence in the lumen of the stomach.
Existing IG balloons are typically single balloons, but may be multiple in number. Their shape may be spherical, cylindrical or pear shaped, the final fill volume generally ranges from 200-700 ml. Generally, the outer shell of the balloon is constructed from an elastomer such as silicone or polyurethane. Expansion of the IG balloon is achieved through instillation of physiologic saline or a relatively inert gas via a fill tube which extends from the balloon itself up the esophagus and exits the mouth. Once the balloon has been fully expanded, the fill tube is disengaged from the balloon by application of pressure on the fill tube, which separates the tube from the balloon at a specially designed port location on the wall of the balloon. As noted, IG balloons are inserted into the stomach in a deflated state using an endoscope to perform a pre-deployment evaluation of the integrity of the esophageal mucosal, its anatomy and that of the stomach as well. The balloon is then inflated by syringe or pump injection of a predetermined volume of saline or by pressurized instillation of an inert gas, e.g., nitrogen.
As noted, gastric distension caused by the balloon as well as by the presence of food stimulates various neuroreceptors located in the stomach wall and causes the patient to experience a feeling of fullness during the experience of food consumption. Continued use of the balloon typically results in a decrease in the daily caloric intake by the patient and subsequently a loss in body weight. Though quite effective in assisting in weight loss, a well recognized finding is that of a diminishing return with the passage of time. For reasons not fully understood, the effectiveness of IG balloons in appetite suppression seems to decline in many patients after approximately six (6) months. For this reason, it is commonly recommended that IG balloons be defeated and removed after that general time period, with the possibility of reinsertion at a later time.
Additional approaches for treating obesity include implanting prosthetics within the stomach wall that bias the stretch receptors in the stomach by pre-stretching and thereby inducing an early sensation of satiety, for instance, as described in US Pat. Pub. No. 2005/0245957 to Starkebaum, et al. As would be understood in the art, “stretch receptors” located within the wall of the stomach are coupled to the central nervous system via the afferent (going away from the stomach and towards the brain) and efferent fibers (sending impulses away from the brain towards the stomach and digestive tract) of the vagus nerve, also known as the 12th Cranial Nerve or CNXII.
There also exist systems for treatment of obesity that selectively apply modulating electrical signals to the patient's vagus nerve. Modulating signals may be used to stimulate vagal activity to increase the flow of neural impulses up the nerve, or to inhibit vagal activity to block neural impulses from moving up the nerve, toward the brain, for producing excitatory or inhibitory neurotransmitter release. Such vagus nerve stimulation systems require a stimulus generator and leads having a nerve electrode implanted within the patient's body, in particular, on the vagus nerve or a branch thereof. In use, the stimulus generator is triggered to apply stimulation to the vagus nerve system.
Vagal nerve blockade devices require invasive surgery and general anesthesia, each with its associated elevated risk in obese patients. These procedures are also very expensive and are not covered by medical insurance. Research studies have proven the efficacy of implantable vagus nerve stimulators in weight loss and in the control of Type II diabetes mellitus, a life-threatening condition brought on by obesity, but the invasiveness of the treatment as well as the cost are disincentives to its common use. As can be appreciated, neurostimulators including implanted electrical leads placed around the trunk of the Vagus nerve in the chest or neck as the nerve makes its way to or from the brain, is an invasive solution which is not selective and may be associated with unintended or undesirable sequella including gastric paresis, delayed intestinal transit time, bloating and distension, wound infection, complications associated with anesthesia and complications associated with airway management in the morbidly obese.
By way of background, the vagus nerve is the dominant nerve of the gastrointestinal (“GI”) tract and includes right and left branches connecting the GI tract to the brain. The vagus nerve generously innervates many, if not most of the organs associated with digestion, including, but not limited to, the distal esophagus, the stomach, the large and small intestines, the gall bladder, the pancreas and others. In the lower part of the chest, the left vagus rotates, becomes the anterior vagus, and innervates the stomach. The right vagus rotates to become the posterior vagus, which branches into the celiac division and innervates the duodenum and proximal intestinal tract.
Satiety signals include the stretch of mechanoreceptors, and the stimulation of certain chemosensors. The exact mechanisms leading an individual to satiety are not fully known, but a substantial amount of information has been accumulated.
It is with respect to these and other considerations that the disclosure made herein is presented.